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54 take away 20 equals what.
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In this problem, we need to start with 54 and then take away 20.
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In other words, what’s 20 less than 54.
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This is the sort of calculation where we can use what we know about place value to help.
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54 is made up of five tens and four ones.
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The number that we need to take away 20 just contains two tens.
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Let’s take away one ten at a time until we’ve taken away two tens.
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Here’s 54.
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And this is what happens if we take away one lot of ten.
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We’re left with four tens and four ones, which is the same as 44.
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Let’s take away another lot of ten.
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Here’s 44.
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And here’s what happens if we take away another ten.
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We’re left with three tens and four ones.
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44 take away 10 equals 34.
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By taking away 10 and then another 10, this is the same as taking away two lots of ten or 20.
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54 take away 20 equals 34.
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Notice how only the digit in the tens place changes as we take away the tens.
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The ones digit stays the same, 54, 44, 34.
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The number of tens in our number change from five tens to three tens because five take away two equals three.
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Another way we could find the answer is using a hundred square to help us.
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Here’s part of a hundred square.
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The good thing about hundred squares is that we can count in tens quickly using them.
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If we look at the numbers that go down a column, it’s the same as counting forwards in tens.
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And if we look at the numbers going up a column, this is the same as counting backwards in tens, which is what we need to do when we take away 20.
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Start with 54 and then move up two squares to count back 20, 54, 44, 34.
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If we count back two tens from 54, we reach 34.
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And so we can say 54 take away 20 equals 34.